Bottled water and fruit juice are found in more school vending machines than any other food or drink item, according to a survey of food service directors in 228 Pennsylvania high schools.

The survey -- conducted by researchers at Pennsylvania State University and the Pennsylvania Department of Health -- found that 71 percent of the schools offer water in their vending machines and 67 percent offer fruit juice.

Researchers said the results suggested that schools are making an effort to "make more-nourishing beverage options available to students."

But the survey found that nearly 60 percent of the schools still sell carbonated beverages in their vending machines.

And in the 67 schools where school stores sold food items, the top-selling items were candy bars and other forms of candy.

Researchers also asked food service directors about their a la carte food sales.

They found that the top-selling a la carte items sold at the high schools are hamburgers, pizza and sandwiches.

Top-Selling A La Carte Items

1. Hamburgers, pizza and sandwiches (77.1 percent listed in the five top-selling items)
2. Cookies, crackers, cakes, pastries and other baked goods not low in fat (68.3 percent)
3. French fries (52.4 percent)
4. Salty snacks not low in fat (44.9 percent)
5. Carbonated beverages (42.3 percent)
6. Water (36.6 percent)
7. Ice cream or frozen yogurt not low in fat (36.1 percent)

The study measured the schools' "competitive food sales" -- food choices from other sources than the school lunch program, including vending machines, snack bars and fundraisers.

The survey found that a la carte sales provide an average of about $700 per day to the schools' food service programs, "almost 85 percent of which receive no financial support from their school districts," according to researchers.

"Competitive food sales appear to be providing needed funding for the schools and school foodservice programs, as other funding sources are decreasing," the researchers wrote.

"Although it has not been determined if there is a relationship between public funding for education or foodservice and the sale of competitive foods, decisions will need to be made that balance the schools' ongoing need for funding with the nutritional needs of students," the researchers added.

The research is published in The Journal of the American Dietetic Association.